The economy, health and education have been the focus of the first three weeks of the campaign.

However, the environment has proven to be a well-trodden battleground in federal elections over the past two decades.

Tony Abbott’s crusade against Labor’s carbon tax helped propel him into office in 2013, despite Kevin Rudd’s best efforts to bring forward the start of the emissions trading scheme.

In 2010, both major parties made announcements on climate change, the health of the Murray-Darling system, marine parks, Queensland’s controversial wild rivers laws and forestry.

In 2007, Rudd’s promise to ratify the Kyoto protocol and take strong action on climate change helped convince thousands of voters to unseat the Howard coalition government.

John Howard himself kicked around the idea of an emissions trading scheme, having realised tackling issues such as water and climate were not only good for the environment but made economic and electoral sense.

Coming into the 2016 election, Bill Shorten and Malcolm Turnbull are both passionate believers that climate change represents a serious global threat.

Turnbull was rolled by his own party in 2009 over his support for Labor’s ETS and has been forced to embrace Abbott’s direct action plan, despite evidence of its ineffectiveness and voter confusion over what he really believes. Shorten says separate emissions trading schemes for the electricity sector and industry, coupled with a target of 50 per cent renewable energy by 2030, is the way to go.

For both major parties, there are votes to be won in talking up the benefits of jobs and economic growth from renewable energy, clean technology, greener farming practices and ensuring the long-term health of the Great Barrier Reef.

There are big electoral benefits for strong environmental policy.

Younger voters, especially, rate climate and the environment among their top concerns and if Labor or the coalition are to woo them away from the Greens they will need to come out early with some impressive policy.

A policy misstep by Labor could cost the party valuable Greens preferences.